The invention relates to check-valves of the variety in which multiple like valve members (petals) are hinged for independent coaction with the respective valve-seat openings in a seating plane; in the case of a double-petal valve, said openings are defined by a seat post which extends diametrically across the bore of the valve body. Check valves of this character are illustratively described in U.S. Pat. Nos. 2,877,792 (Tybus), No. 3,538,946 (Hilsheimer), No. 3,678,958 (Satterwhite, et al.), and No. 4,079,751 (Partridge, et al.).
In the foregoing patents and in all other similar check valves known to me, the valve body includes or carries a fixed stop against which the valve members abut to determine their full-open position. For certain applications, the provision of such a stop entails complexity of body construction and mechanical shock associated with attainment of the full-open position of the valve. Such shock is aggravated under conditions of frequent and intermittent demand for full-flow use of the valve.